Guitar incorporating inertial vibrato device



March 22, 1966 c. L. FENDER 3,241,418

GUITAR INCORPORATING INERTIAL VIBRATO DEVICE Filed June 5, 1964 I 2Sheets-Sheet 1 INVENTOR. 6'1 A/PE/VCE L. PZ'NDE/Q BY W Arrow/1s VJ March22, 1966 c. L. FENDER GUITAR INGORPORATING INER'IIAL VIBRATO DEVICEFiled June 5, 1964 2 Sheets-Sheet 2 INVENTOR. 62,4 xe /vczs L. FENDEQArray/vac United States Patent O 3,241,418 GUITAR INCORPORATING INERTIALVIBRATO DEVICE Clarence L. Fender, Fullerton, Calif., assignor, by mesneassignments, to Columbia Records Distribution Corp.,

New York, N.Y., a corporation of New York Filed June 5, 1964, Ser. No.372,908

14 Claims. (Cl. 84-313) This invention relates to a vibrato constructionfor guitars and the like, and to a guitar incorporating such vibratoconstruction.

A primary object of the invention is to provide a vibrato device which,although light in weight and highly compact, is characterized by asurprisingly great inertial effect.

Another object is to provide a guitar incorporating a vibratoconstruction which requires relatively little effor to operate, therelationship being such that the effects resulting from tensioning andslackening of the strings are compensated for automatically byvariations in the moment arms through which the compensating springmeans operate.

An additional object is to provide a combination vibrato and bridgeconstruction for guitars, such construction being highly compact inorder to prevent or minimize interaction between the operative stringportions and the string portions between the bridge and the vibrato.

.An additional object is to provide a guitar incorporating a vibratodevice which is extremely simple to assemble and adjust, regardless ofvariations in the characteristics of the particular guitar strings or ofthe springbiasmeans.

These and other objects'will become apparent from the following detaileddescription taken in connection with the accompanying drawings in which:

FIGURE 1 is a perspective view illustrating a guitar incorporating theinertial vibrato device;

FIGURE 2 is an enlarged fragmentary sectional View taken generally online 22 of FIGURE 1, and showing the vibrato in various pivotedpositions adapted to thereby vary the string tension and produce avibrato effect;

FIGURE 3, is a fragmentary plan view illustrating the vibrato and bridgeportions of the guitar;

FIGURE 4 is an enlarged fragmentary sectional view on line 44 of FIGURE3;

FIGURE 5 is a fragmentary bottom view of the vibrato device, as viewedfrom the plane 5 5 indicated in FIG- URE 2; I

FIGURE 6 is an enlarged transverse sectional view taken generally online 6-6 of FIGURE 3 and corresponding to portions of FIGURE 2, aneutral position being illustrated when the device is adjusted to acondition such that the levers are not perpendicular to the base plate;

FIGURE 7 is a view corresponding to FIGURE 6 but 3,241,418 Patented Mar.22, 1966 illustrating a second adjusted condition such that the leversare substantially perpendicular to the base plate; and

FIGURE 8 is a diagrammatic view indicating variations in the moment armthrough which the compensating spring means operate, which variationsoccur in response to pivoting of the levers and are such as tocompensate automatically for variations in string tension resulting fromsuch pivoting.

Referring first to FIGURE 1 of the drawings, the invention isincorporated in a guitar having a body 10, a neck 11 and a head 12. Theguitar is illustrated as being of the solid-body type, including afinger board or face plate 13 which is suitably mounted on the uppersurface or face of the body 10. Other conventional components include anelectromagnetic pickup (FIGURE 2), and suitable tone and volume controls15 adapted to control the characteristics of the electrical signalgenerated by the pickup in response to vibration of the strings 16-21.

The guitar strings 16-21, which are formed of a suitable magnetizablematerial, are extended in stretched or tensioned relationship betweentuning screws 23 (on head 12) and the vibrato device 24 of the presentinvention. The arrangement is such that the strings lie generally in asingle plane (or on a small section of an imaginary large-diametercylinder) which is generally parallel to the face plate 13.

The vibrato device 24, and a bridge 25 which is closely associatedtherewith as will be described hereinafter, include a strong metal baseplate 26'which is rigidly anchored, as by screws 27, to the guitar body10 adjacent face plate 13. Openings 28 (FIGURES 6 and 7) are provided inbase plate 26 along a line transverse (preferably perpendicular) to theguitar strings 1621, in order that fulcrum portions 29 will be formed.Such fulcrum portions 29 are adapted to support pivotal movement of aninertial string-mounting means 30 next to be described.

The inertial string-mounting means 30 comprises a metal bar extendingtransversely (preferably perpendicularly) to the strings 16-21 above theopenings 28. The illustrated bar is formed of steel and is generallycylindrical in shape, the diameter of the cylinder being suflicient tocause the bar to have the requisite mass as will be describedsubsequently.

First-class levers 32 are employed to effect the aboveindicated pivotalassociation between the inertial stringmounting means 30 and the fulcrumportions 29 of base plate 26. The levers are preferably identical toeach other, each extending through one of the openings 28. Each lever 32comprises a lower portion 33 disposed beneath base plate 26 andconnected to a tension spring 34, a pivot portion 36 disposed in opening28 and pivotally associated with a fulcrum portion 29, and an upperportion 37 disposed above the base plate 26 and connected to theinertial member 30.

The lower portion 33, which preferably has a diameter larger than thatof opening 28 in order to prevent accidental movement of the leverupwardly therethrough, has a reduced-diameter lower end in order toprovide a shoulder 38 (FIGURES 6 and 7) adapted to seat the hook-shapedend 39 of the associated tension spring 34 which is of the helical-wiretype. The relationship is such that the entire lever 32 may be rotatedabout the longitudinal axis thereof without in any way disturbing theconnection between the lower lever end and the spring 34.

The pivot portion 36 of each lever comprises a V-sectioned annulargroove adapted to effect substantially friction-free pivotal associationwith fulcrum portion 29 of the base plate. The fulcrum portion 29 ispreferably formed by countersinking opposite sides of base plate 26 toprovide frustoconical surfaces which meet at a sharp fulcrum edge. Theangle between such frustoconical surfaces is substantially smaller thanthe angle between the frustoconical walls which define the V-sectionedannular groove 36, so that the lever may pivot as desired. Such pivotalmovement -is about an axis which is contained in the base plate 26 andextends transversely (preferably perpendicularly) to the guitar strings.

The upper portion 37 of each lever is shown as being externally threadedfor threaded insertion into a corresponding internally-threaded opening41 in the stringmounting bar 30. A hexagonally-shaped socket 42 isformed in the upper end of lever portion 37 for reception of a wrench,the latter being adapted to be inserted through an opening 43 whichforms an extension of the opening 41. In this manner, the entire lever32 may be rotated about the longitudinal axis thereof in order to adjustthe distance between the string-mounting means 30 and the pivot axisthrough base plate 26. This provides an important advantage relative toadjustment of the neutral position of the vibrato device, as will bediscussed subsequently relative to FIGURES 6 and 7.

The ends of strings 16-21 are directly connected to the inertial means30, in the absence of any intermediate bars, levers or connectors, asbest shown in FIGURE 4. Thus, each string end is extended beneath thebar 30 and through a horizontal passage 45 into a recess or counterbore46. An eyelet 47 is mounted at the string end in the usual manner, toprevent movement thereof through the passage 45. The extension of thestring end beneath the inertial member 30, instead of thereabove,insures that the requisite downward pressure will be brought to bear onthe bridge 25.

The bridge 25 is a rocking or pivoting bridge which may be identical tothe one described in my previous Patent No. 2,972,923, issued February28, 1961, for Floating Tremolo and Bridge Construction for Lute- TypeMusical Instruments.

Such a bridge has string-contacting barrels 48 which are supported on achannel 49 having legs or posts 51 which extend downwardly into sockets52, the latter being suitably mounted in the support plate 26 and guitarbody 10. The sockets 52 are sufficiently large to permit pivoting of thelegs or posts 51 therein, so that the bridge rocks as the strings 16-21are moved in response to pivoting of the levers 32. Therefore, there isno relative movement between the bridge and the strings, and no rubbingor wearing engagement therebetween.

It is a feature of the present invention that the bridge 25 may bedisposed very close to the vibrato device 24. This produces an advantagein that the lengths of the string sections between the bridge andvibrato may be extremely short, thus preventing substantial interactionbetween such string section and harmonics in the operative stringsections (which extend between bridge 25 and the second bridge 53,adjacent head 12).

Proceeding next to a further description of the tension springs 34,which provide a spring bias compensating for the tension of strings16-21, these are mounted in suitable slots or recesses 55 (FIGURE formedin guitar body 10. In order to permit the desired close spacing betweenthe bridge 25 and the vibrato device 24, the springs 34 and the slotstherefor are caused to converge in the direction toward head 12, theresult being that the slot and spring ends are located between thebridge posts 51 as illustrated. The spring ends adjacent head 12 aresuitably hooked to slit portions 56 of the base plate 26, in a mannerwhich permits upward and downward pivoting of the springs withouteffecting distortion thereof.

The springs 34 are sufliciently tensioned that the coils thereof areseparated considerably, thereby permitting the lower ends of levers 32to pivot toward the head 12 without eliminating the spring tension.

The remaining element in the apparatus comprises a crank 57 which isconnected to one end of the stringmounting bar 30, extending therefromto a position adjacent the operative portions of the strings. The mannerof connecting the crank to the bar 30 is such that depression or raisingof the crank causes pivoting of the levers 32 to the positionsillustrated in FIGURE 2 and to various intermediate positions. The crankis also adapted to pivot about a generally vertical axis, as describedin my previous Patent No. 2,741,146, issued April 10, 1956, for aTremolo Device for Stringed Instruments, in order to permit movement ofthe end thereof with the hand of the guitarist.

A suitable nylon friction element 58, with associated set screw 59(FIGURE 3) should be provided in order to prevent undesired pivoting (orplay) of the crank about the vertical axis.

Description of various critical relationships, operations and advantagesThe inertial string-mounting means 30 should have a mass sufiicientlylarge to resist vibrations induced by at least the higher-pitched onesof strings 16-21, so that the strings vibrate in a sustained manner asis desired. Furthermore, the mass should be suflicient to prevent thestrings from interacting with or modulating each other. It has beenfound that, in the present construction wherein the strings areconnected directly (over the rocking bridge 25) to an inertial memberwhich is pivotally supported in floating relationship (the stringtension being balanced by the spring means) above the base plate 26, themass of the inertial member may be surprisingly low and still achievethe requisite results. For example, the mass of bar 30 may beapproximately three ounces. This results in important advantagesrelative to portability, manufacturing costs, etc.

It will be understood that, during the mass production of guitars, thetension exerted by various springs 34 will vary within a considerablerange. Furthermore, the tension exerted by the guitar strings 16-21varies considerably. According to .one important feature of the presentinvention, the results of such variations may be readily compensated forby merely rotating the levers 32 about their longitudinal axes, by meansof wrenches inserted through openings 43 into sockets 42 as statedabove. 7

Referring to FIGURE 6, the illustrated adjusted condition is such thatthe string-mounting bar 30 is relatively remote from base plate 26, sothat the lever arm through which the strings act is relatively long.Therefore, the illustrated neutral position is such that the levers 32are pivoted somewhat clockwise from the vertical. This may becompensated for by merely rotating the levers 32 in directions effectinglowering of the string-mounting bar 30 to the position shown in FIGURE7, for example. The illustrated neutral position is then such that thelevers 32 are vertical, that is to say perpendicular to base plate 26.Particularly for reasons to be described below, it is preferred that theneutral or floating position (at which the spring bias exactlycounterbalances the string tension, with no force being ex- 5 ertecl oncrank 57) occur when the levers 32 are vertical as shown in FIGURE 7.

Referring next to schematic FIGURE 8, the solid line 33b represents thelower portion 33 of lever 32, when the same is perpendicular to baseplate 26. Thus, the angle 9 is the same in FIGURE 7 and in FIGURE 8, itbeing understood that the solid line 34b represents the axis of eachspring 34. The horizontal line 26 represents the base plate, whereas thecenter of the indicated semicircle in FIGURE 8 represents the fulcrumportion 29 of the base plate.

The lines 33a and 330 represent substantially the extreme pivotedpositions of each lower lever portion 33, whereas the lines 34a and 340represent the corresponding pivoted positions of each tension spring 34.

It is emphasized that the angle is substantially less than ninetydegrees, and that the relationship should not be such that such angleover becomes more than ninety degrees regardless of the pivoted position(within the usual range of vibrato operation) of the lever portion 33.Because of this relationship, raising of the crank 57 (FIGURE 2) willcause the tension spring 34 to operate through a progressively longermoment arm (for example, coincident with line 330) relative to fulcrum29, as is desired in order to counteract the resulting increased stringtension. Conversely, lowering of crank 57 will cause the spring 34 tooperate through a progressively shorter moment arm, as is also desiredin that the string tension is thereby lessened and requires less forceto counteract. For example, the short moment arm relative to line 33a isshown at 60.

Thus, it will be observed that the moment arm 60 through which spring34a operates when the lever is in the 33a position is very much shorterthan is the moment arm through which spring 34c operates when the leveris in the 33c'position. As the result of such relationship, the crank 57may be manually operated with a very minimum of force or effort.

In summary, therefore, the described vibrato device 24 and associatedbridge means 25 are very lightweight, simple and economical, yet producemany advantages some of which will next be briefly re-stated.

(1) The string ends are directly connected to the inertialstring-mounting element 30, which floats above plate 26, therebyresulting in a surprisingly great inertial ettect for an inertialelement of given mass.

(2) The crank 57 may beoperated with a minimum of etfo-rt, because ofthe automatically-compensated bias action of springs 34 as described indetail above.

(3 The vibrato device may be readily adjusted to compensate forvariations in spring bias and string tension, merely by rotating thelevers 32 about their longitudinal axes as described relative to-FIGURES. 6 and 7.

(4) The bridge 25 may be mounted very close to the vibrato device 24, instraddling relationship relative to the ends of springs 34, therebycausing the string sections between the bridge and vibrato to be veryshort in order to minimize interaction with harmonics in the operativestring portions.

(5) The string ends are mounted beneath the stringmounting element 30 inorder to provide the requisite downward pressure on the bridge 25,Without the necessity of providing additional bearing elements.

(6) The combination vibrato and bridge construction is highly compact,and attractive in appearance.

The use of the term bodily in the appended claims denotes substantiallytranslational movement of the stringmounting element 30, and is to bedistinguished from mere rotation of such element about its ownlongitudinal axis.

The foregoing detailed description ;is to be clearly understood as givenby Way of illustration and example g only, the spirit .and scope of thisinvention being limited solely by the appended claims.

I claim: 1. A guitar-type musical instrument, which comprises: a body, aplurality of guitar strings mounted over said body in tensionedrelationship, an inertial string-mounting element having sufficient massto resist vibrations induced by at least the higher-pitched ones of saidstrings, means to connect said guitar strings directly to saidstring-mounting element, means to mount said string-mounting element inspaced relationship above said body and in a floating manner such thatsaid string-mounting element may be moved bodily relative to said bodyin directions changing the degree of tension in said strings and thusthe pitch thereof, and means to move said string-mounting element bodilyin said directions. 2. A guitar-type musical instrument, whichcomprises: a body, a plurality of guitar strings mounted over said bodyin tensioned relationship, an inertial string-mounting element havingsuflicient mass to resist vibrations induced by at least thehigher-pitched ones of said strings, means to connect said guitarstrings directly to said string-mounting element, means to mount saidstring-mounting element in spaced relationship above said body and in afloating manner such that said string-mounting element may be movedbodily relative to said body in directions changing the degree oftension in said strings and thus the pitch thereof,

said means including springs arranged to counteract the tension of saidstrings, means to move said string-mounting'element bodily in saiddirections, and movable bridge means to space said strings above saidbody, said bridge means being adapted to move with said strings,

said bridge means being independent of said stringmounting element. 7 i3. A guitar-type musical instrument, which comprises: a body, aplurality of guitar strings mounted over said body in tensionedrelationship, an inertial string-mounting element disposed above saidbody and having suflicient mass to resist vibrations induced by at leastthe higher-pitched ones of said strings, .means to connect said guitarstrings directly to said string-mounting element, fulcrum meanssupported on said body, leve-r means having an intermediate portionpivotally associated with saidfulcrum means, means to connect one endportion of said lever means to said element, spring means operativelyassociated with the other end portion of said lever means and with saidbody,

said spring means being sufliciently strong to balance the tension ofsaid strings and cause said lever means to remain norm-ally in a neutralposition, and means to pivot said lever means about said fulcrum meansto shift said lever means in either direction away from said neutralposition, thereby moving said element and changing the degree of tensionin said strings. i 4. A guitar-type musical instrument, which comprises:a body, a plurality of guitar strings mounted oversaid body in tensionedrelationship, an inertial string-mounting means having suflicient massto resist vibrations induced by at least the higher-pitched ones of saidstrings, means to connect said guitar strings directly to saidstring-mounted means, fulcrum means supported on said body, lever meanshaving an intermediate portion pivotally associated with said fulcrummeans, means to connect one end portion of said lever means to saidstring-mounting means, spring means operatively associated with theother end portion of said lever means and with said body,

said spring means sufficiently strong to balance the tension of saidstrings and cause said lever means to remain normally in a neutralposition, means to pivot said lever means about said fulcrum means toshift said lever means in either direction away from said neutralposition, thereby moving said string-mounting means and changing thedegree of tension in said strings, and adjustment means to vary thedistance between said fulcrum means and at least one of the meansconnected to said lever means, thereby determining said neutralposition. 5. A guitar-type musical instrument, which comprises: a body,a plurality of guitar strings mounted over said body in tensionedrelationship, fulcrum means provided on said body, elongated first-classlever means having an intermediate portion pivotally associated withsaid fulcrum means, means to connect one end portion of said lever meansto said strings, tension spring means operatively connected to the otherend portion of said lever means and also connected to said body,

said spring means being sufficiently strong to balance the tension ofsaid strings and thereby cause said lever means to remain normally in aneutral position, means to pivot said lever means about said fulcrummeans to shift said lever means away from said neutral position andthereby change the degree of tension in said strings, and means toadjust through small increments the distance between said fulcrum meansand at least one of the elements connected to said lever means, therebydetermining said neutral position and compensating for factors includingthe tension of said strings and the characteristics of said springmeans. 6. A guitar-type musical instrument, which comprises: a body, aplurality of guitar strings mounted over said body in tensionedrelationship, fulcrum means provided on said body, an elongatedfirst-closs lever having an intermediate portion pivotally associatedwith said fulcrum means, means to connect one end portion of said leverto said strings, elongated tension-spring means connected between theother end portion of said lever and said body to balance the tension ofsaid strings and thus cause said lever to remain normally in a neutralposition, said spring means being disposed at an acute angle relative tosaid lever when the same is in said neutral position, and means to pivotsaid lever about said fulcrum means to selectively increase and decreasethe tension in said strings,

said elements being related in such manner that the size of said acuteangle is increased when the tension in said strings is increased wherebyto increase the moment arm through which said spring means acts andthereby compensate for said increased tension in said strings, and insuch manner that the size of said acute angle 1 is decreased when thetension in said strings is lessened whereby to reduce said moment armand thus compensate for the decreased tension in said strings.

7. In combination with a guitar-type musical instrument having a bodyand a plurality of guitar strings mounted over said body in tensionedrelationship, a combination vibrato device and bridge mounted on saidbody and operatively associated with said strings, said vibrato deviceand bridge comprising:

an inertial string-mounting element having substantial mass,

means to pivotally associated said string-mounting element with saidbody to permit movement of said string-mounting element to effectvariations in the tension in said strings,

bias means to cause said string-mounting element to remain normally in apredetermined neutral position,

a bridge element pivotally mounted on said body in supportingrelationship relative to said strings,

said bridge being disconnected from said stringmounting element, and

means to move said string-mounting element to thereby vary the tensionin said strings and also effect pivotal movement of said bridge.

8. The invention as claimed in claim 7, in which said strings areextended over said bridge and beneath said string-mounting element, andin which means are provided to connect the ends of said strings to saidstringmounting element by extending said string ends generallyhorizontally through said string-mounting element at r points locatedabove the lower region of said stringmounting element.

9. A vibrato device for guitar-like musical instruments, whichcomprises:

a base plate having first and second openings therein, first and secondlevers inserted, respectively, through said openings,

said levers and the portion of said base plate defining said openingbeing shaped to permit pivoting of said levers about an axis extendingbetween said openings and also to permit rotation of each of said leversabout the longitudinal axis thereof without interfering with saidpivotal movement about said axis,

an inertial string-mounting bar having substantial mass and extendinggenerally parallel to said base plate above said openings,

said bar having threaded openings therein to threadedly receive theupper ends of said levers whereby rotation of said levers about thelongitudinal axes thereof will effect raising and lowering of said barrelative to said base plate, means to connect the ends of guitar stringsdirectly to said bar in spaced relationship therealong, and tensionsprings connected to the ends of said levers remote from said bar in amanner permitting rotation of said levers about the longitudinal axesthereof.

10. The invention as claimed in claim 9, in which said tension springscomprise elongated helical springs the ends of which remote from saidlevers are connected to said base plate, said springs being disposed atacute angles relative to said levers when said levers are perpendicularto said base plate.

11. The invention as claimed in claim 9, in which said bar hasWrench-openings formed therein adjacent the threaded openings therein,and in which the threaded ends of said levers have wrench sockets formedtherein, whereby said levers may be rotated about the longitudinal axesthereof by means of wrenches inserted through said wrench-openings insaid bar.

12. The invention as claimed in claim 9, in which said base plate hasconvergent frustoconical surfaces formed at said openings whereby knifeedges are formed in said openings, and in which said levers have annulargrooves of V-shaped section, the angle between the walls of each of saidgrooves being substantially greater than that between said convergentfrustoconical surfaces.

13. The invention as claimed in claim 9, in which a bridge is mounted onsaid base plate in spaced relation- 10 References Cited by the ExaminerUNITED STATES PATENTS 2,741,146 4/1956 Fender 843 13 2,972,923 2/1961Fender 84307 X 3,056,329 10/ 1962 Butts 84-313 3,162,083 12/ 1964Webster 84313 FOREIGN PATENTS 942,999 11/1963 Great Britain.

LOUIS J. CAPOZI, Primary Examiner.

LEO SMILOW, Examiner.

C..M. OVERBEY, Assistant Examiner.

1. A GUITAR-TYPE MUSICAL INSTRUMENT, WHICH COMPRISES: A BODY, APLURALITY OF GUITAR STRINGS MOUNTED OVER SAID BODY IN TENSIONEDRELATIONSHIP, AN INERTIAL STRING-MOUNTING ELEMENT HAVING SUFFICIENT MASSTO RESIST VIBRATIONS INDUCED BY AT LEAST THE HIGHER-PITCHED ONES OF SAIDSTRINGS, MEANS TO CONNECT SAID GUITAR DIRECTLY TO SAID STRING-MOUNTINGELEMENT, MEANS TO MOUNT SAID STRING-MOUNTING ELEMENT IN SPACED